Analgesics, and more particularly opioid or morphine derivatives, are often misused. Such misuse can be intentional or unintentional consumption of a solid oral drug containing an analgesic active principle, for a purpose other than that which is officially approved by the competent health authorities. This is a very complex and difficult problem to solve. The reason is that drug abuses and unfortunately now even teenagers have found way to recover the drug from tablets quite easily.
For example, today, teenagers prepare for parties on Saturday, a cocktail of vodka with Oxycodon that they extract easily from tablets, with water or alcohol. The process consists in crushing the tablet and pouring the powder into a glass of vodka or water and then, to wait long enough to extract almost completely all the morphines derivative. They use to do the preparation of the drug before they take it. This practice is widespread in US but also in Europe. This is becoming a real social concern addressed by social agencies but also by the Food and Drug Administration in US and European Agencies, who wish that dosage forms preventing misuse be developed.
There are other ways to misuse the type of opoïd such as extracting the drug as described above and make an intra-venous injection or dry the drug in order to obtain a powder which can be inhaled.
There is a prior art describing different solution to avoid the misusage of opioids contained into a delivery systems.
Our understanding is that patent application US-A-2003/0224051 describes osmotic delivery dosage forms for the modified release of oxycodone. The dosage form comprises an oxycodone core or acceptable salts thereof, a semi-permeable membrane at least partially surrounding the core, an exit orifice through the membrane allowing the release of oxycodone. This type of tablet allows an easy extraction by water for example after 12 hours or more and consequently does not provide i.a. a satisfactory solution against misuse.
Another way to avoid misuse of an opioid is to combine the opioid with its antagonist such as naltrexone. Our understanding is that patent application WO-A-03/013479 patent describes an oral dosage form comprising a therapeutically effective amount of an opioid analgesic; an opioid antagonist (naltrexone); and a bittering agent. When the drug abuser crushes the tablet, the opioid and its antagonist are released and the opioid effect is neutralised.
This system does not prevent i.a. extraction by water because, without crushing, the opioid can be extracted, contrary to naltrexone.
Our understanding is that published European patent application EP-A-1293209 describes a solid oral pharmaceutical dosage form with reduced potential for drug abuse. The oral dosage form of the invention is a sustained release dosage form based on an ion exchange resin which contains an opioid derivative. However, this dosage form does not prevent solvent extraction with an extraction time longer than the normal release time of the drug. If said oral dosage form is left in a glass of water during 24 hours, most of the drug will be extracted.
As can be seen from the foregoing presentation of the prior art, different solutions are provided to prevent misuse of pharmaceutical opioids in modified release solid dosage forms.
However, our understanding is that none of the solutions can prevent i.a. the extraction by water, alcohol or any other type of drinkable solvent.